When did you feel it?
Is it soft, firm or hard?
2 months ago
It is same size or is increasing in size?
This is most likely to be non bleeding hemorrhoids/piles. One of the commonest swelling in the anal region, not increasing in size is piles. If constipation and hard stools are avoided, they don't bleed. Warm sitz bath may reduce the size but usually a surgical excision is required.
Please feel free for your follow up questions.
You are welcome.
Best wishes and kindest regards.